Discovery Undocks from Space Station, Heads Back to Earth

The seven astronauts of Discovery's STS-114 mission say farewell to the Expedition 11 crew aboard the International Space Station (ISS) on Aug. 6, 2005. In the forefront, STS-114 pilot James Kelly recieves a warm sendoff from Expedition 11 commander Sergei Krikalev. CREDIT: NASA TV.

HOUSTON - After eight days docked at the International Space Station (ISS), the shuttle Discovery cast off from the orbital laboratory Saturday and began the trip back to Earth.

Discovery's seven STS-114 astronauts exchanged hugs and handshakes with the space station's two-man Expedition 11 crew then closed the hatches between their spacecraft at about 1:14 a.m. EDT (0514 GMT).

"We thank them for being such great hosts and we're so happy to have spent time up here with them," STS-114 commander Eileen Collins told the station's Expedition 11 crew before closing the hatches. "These are memories that we will have forever."

Discovery is scheduled to land Monday at 4:46 a.m. EDT (0746 GMT) at Kennedy Space Center (KSC) in Cape Canaveral, Florida.

Shuttle pilot James Kelly flew Discovery during today's undocking, which occurred on time at 3:24 EDT (0724 GMT), then guided the orbiter on a fly-around maneuver that circled the space station at a distance of about 400 feet. His fellow STS-114 crewmembers photographed the station during the maneuver.

"We have physical separation," Collins said, as the two spacecraft undocked.

Collins and her six fellow STS-114 astronauts are the first shuttle astronauts to visit the ISS since the Endeavour orbiter left the station in December 2002. Their mission, NASA's first shuttle flight since the 2003 Columbia tragedy, delivered tons of fresh supplies to the station and is carrying tons more trash and broken or unneeded equipment back to Earth.

The STS-114 crew spent eight days, 19 hours and 54 minutes at the ISS after docking at the station on July 28.

"We're not glad to see you go," Expedition 11 flight engineer John Phillips told the STS-114 crew. "Great flight, soft landing, and we look forward to seeing you back in Houston in a few months."

While Discovery will land Monday, the Expedition 11 astronauts must wait until October - and the end of their six-month stay aboard the ISS - to return to Earth.

During their flight, Collins and her crew staged three spacewalks and tested out heat shield repair techniques and an orbital inspection boom tipped with laser and camera sensors to scan for cracks and other damage. Those measures were part of NASA's effort to enhance shuttle flight safety in response to the loss of seven STS-107 astronauts aboard the Columbia orbiter, which suffered foam debris damage to its heat shield during launch and subsequently broke apart over Texas during reentry on Feb. 1, 2003.

In addition to replacing a vital gyroscope used to maintain the station's attitude control, STS-114 astronauts swapped out experiment packages and installed a spare parts platform - with spare parts included - to ISS' exterior.

STS-114 spacewalker Stephen Robinson also performed the first-ever in-flight repair of a shuttle's heat shield when used the fingers on his right hand to remove two strips of space-filling material from between the tiles lining Discovery's belly.

"It's really been such a fantastic experience," Collins told Sen. Kay Bailey Hutchinson (R-Texas) Friday during an Earth-to-space phone call. "I'm looking forward to seeing my family again."

There may be an extended gap between Discovery's ISS mission and the next shuttle mission. NASA officials said Friday that the agency's second return-to-flight mission, Atlantis' STS-121 spaceflight, will launch no earlier than Sept. 22 - pushed back from Sept. 9 - to allow engineers to study and fix an external tank foam insulation shedding problem seen during Discovery's launch.

As Discovery shot into space, a nearly 1-pound piece of foam fell from its external tank - it did not hit the orbiter - in a similar manner to the foam loss that crippled Columbia's heat shield. NASA officials said they will not launch another shuttle until the foam debris issue is resolved.

"Space exploration isn't easy," Collins said told Congressman Tom DeLay (R-Texas) in the Friday phone call. "Not everything is going to be 100 percent successful, but the important thing is we're learning."

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